The present invention generally relates to environmental control apparatus and, in a preferred embodiment thereof, more particularly relates to an improved liquid spray air purification and controlled humidification system which is automatically operated by a specially designed air quality monitor and controller embodying principles of the present invention.
Interior spaces of homes and other buildings are typically provided with automatically controlled temperatures using one or more air handling units that provide a recirculating flow of air drawn out of the conditioned space, flowed through the air handling unit by an air blower therein, heated or cooled as necessary within the unit, and then flowed back into the conditioned space. In addition to providing the desired temperature control within the conditioned space, air handling units of this general type are also often provided with the capability of purifying, at least to some extent, air flowing through the units.
The most common device used for this air purification task is the familiar replaceable flow-through air filter element that is disposed within the unit cabinet structure in the path of air being forced therethrough on its way back to the conditioned space served by the unit. Filters of this type are typically formed from a matted fibrous material (such as fiberglass) that serves to trap particulate matter, such as dust, borne in the conditioned space return air entering the unit. Additionally, electrostatic air filters are often incorporated in air handling units and provide improved particulate removal performance due to their electrostatic attraction and trapping of particulates substantially smaller than the ordinary fibrous filter can effectively capture.
However, as is well known, undesirable air pollutants are present in a variety of forms other than the relatively easy to capture particulates that the fibrous and electrostatic filter structures are designed to remove from the recirculated air from the conditioned space. Another known type of air purification process is the use of a liquid spray, typically a water spray, directed against filter element through which air to be supplied to a conditioned space is flowed. The liquid spray is maintained in continuous contact with the flowing air traversing the filter element, and, depending on the type of air purification system in which it is incorporated, serves to entrain a variety of airborne particulates as well as other types of pollutants such as aerosols, nitrogen oxides, sulfur oxides, carbon dioxides and monoxides, hydrogen sulfides and hydrocarbons, and then be drained away carrying entrained pollutants with it. This general type of air purification system also desirably serves to humidify the air delivered to the conditioned space.
Despite the pollution removing effectiveness of various known types of liquid spray air purification systems, their use has typically been limited to industrial and commercial applications, as opposed to residential applications, due to reasons such as excessive humidity and lack of humidity control, complexity, cost and increased maintenance requirements compared to dry filtering systems. Because of the increased awareness of air polluting materials, and the desirability of removing them from residential environments, it is seen as desirable to provide a liquid spray air purification system that is suitable for incorporation in residential as well as commercial applications. It is accordingly an object of the present invention to provide such a system which will (1) both purify the air and control the humidity of the air delivered to a conditioned space and (2) automatically monitor the air quality and control the operation of the system to economically clean the air and maintain the air quality, temperature, and humidity within desired, selectively variable preset ranges.